I have hit a bit of a snag in my tagging and would like to pick your collective brains.

For movie soundtracks, I use the suffix OST (i.e. "Saturday Night Fever OST"). For cast recordings, I use the suffix OCR (i.e. "The Lion King OCR"). It should go without saying that "OST" and "OCR" means "original sound track" and "original cast recording", respectively. I don't know if this is proper tagging, but it works for me.

I am, however, having problems deciding how I should treat television soundtracks. Since they're not movie soundtracks, I want to use something other than "OST", but I don't know what. I have I've tried "TVST", "OTVST", "OST (TV)", and a few other variants . . . and they just look wrong to my eye.

Can a TV show not have an "Original sound track"? I see nothing in the phrase that says anything about the format the parent work was originally shown on (in theaters, or chopped up into 30/60 minute segments for television broadcast). Besides, you're not tagging the parent work at all - you're tagging audio. It isn't a TV show or a movie. So the question itself is somewhat irrelevant.

As for the "proper" way to do it - there isn't one. There's no recognized standard.

As for what I've done - I use "OST" for both film and video game soundtracks. I don't have any TV soundtracks, but I suppose I'd use OST for those also.

I suppose if you want to be perfectly organized, it'd really belong in a separate field, something like "RELEASETYPE". The name of the release would go under the "ALBUM" tag, with a separate tag to say whether it's an Album, EP, Soundtrack, Single, Audiobook, etc. However, there's not much support for such detailed tagging. So being strictly practical, i've just been sticking (OST) and occasionally (EP) at the end of the ALBUM field.